Added next-move in replays (incompatible with old replay-files)

Quick Briefing:
gs.c (added nextmv field in GameState, (de)serialization adopted)
tui.c (displays next-move right after previous-move in replays)
tui_skin.c (some irrelevant color-changes)
main.c (netxmv of prev gamestate gets updated in _do_play_board())
replays/ (added new sample replay-files, deleted old ones)
Version Bump
Merge pull request #4 from migf1/REPLAY_NEXTMV

Added next-move in replays (incompatible with old replay-files)